First make the dressing by mixing together the oil, vinegar, water, salt, pepper and sugar. When the sugar is dissolved, add the garlic and sliced onion. Refrigerate until cold.

Clean the asparagus, breaking off tough ends. If you wish, peel the stalks for a more tender vegetable. Slice the asparagus stalks into approximately 2 inch pieces.

Add the asparagus to boiling water in a medium saucepan. Cook for about 3 minutes, dump into a colander and quickly rinse with ice water to stop the cooking process. Or, if the dressing is cold enough, toss the asparagus immediately into the cold dressing. Do not overcook the asparagus!

Meanwhile, heat the oil in a frying pan, sautee the chopped scallions for a few seconds and add to the asparagus and dressing. Add the chopped tomato and sesame seeds to the mixture and toss before serving.